Time duration pulse telemetering system



June 15, 1948.

2 Sheets-Sheet 1 Filed Feb. 23, 1946 I ll llll J w n L i a B c w w w ,m/c w w w w m F .15... w B x 55/ a wig Z m, 1=fi j ha y j Amm ammw a M xTW INVENTOR. Walk/H Green, BY @/4&

June-15, 1948. w. H. GREEN TIME DURATION PULSE TELEMETERING SYSTEM 2Sheets-Sheet 2 Filed Feb. 23, 1946 INVENTOR. WQZZerfl Greert,

Patented June 15, 1948 UNITED STATES PATENT OFFICE TIME DURATION PULSEIncorporated, Delaware -l ll.,aoorporationoi Application February 28,1946, Serial No. 640,613

7 Claims. (Cl. 171-351) This invention relates to a positioner ortelemetric receiver.

An object of this invention is to provide means for positioning amovable member in accordance with a remote measurement oi a variablequantity.

It is another object oi this invention, in a remote telemetric receiver.or positioner, to provide an improved means ior a quicker positioning oithe receiver to a position corresponding to a rate oi ilow of liquid atthe remote point.

Other objects oi the invention will be apparent irom the description andclaims which follow.

Many telemetric receivers have been suggested by the prior art anddevices oi this nature fall into several classes. One oi the classes issometimes called the "automatic time interval" type, in which an impulseis initiated at regular intervais, such as one minute, by an electricclock and provides an impulse oi a time duration corresponding to thequantity to be measured. When such a system is used with a positioner orindicator, it is customary for a pointer element to be positioned by anelement driven by a synchronous motor running on current controlled bythe sending, or transmitting, element which permits the flow oi currentior a period corresponding to the quantity to be measured; and a secondelement, moving in the opposite direction from the first, may operate topush the pointer in a reverse direction until it reaches the position ofthe first moving element. This latter movement is necessary to take careoi those contingencies in which the quantity measured in any period isless than that of the preceding cycle. That is, if the positioner ispushed to a position by the previous cycle which corresponds to agreater quantity than that of the then present cycle, it is necessary toreturn the pointer a distance corresponding to the diiierence. In thepast it has been customary to operate both moving elements on spacedtime cycles so that a predetermined time, such as one minute, was alwaysused to secure positioning of the pointer. My invention includes meansfor quickly positioning the pointer to a position corresponding to theflow rate and in one form to immediately initiate a new cycle. Thuswhere the quantity to be measured is low, the transmitting element cantest the flow in very short cycles, therefore more accurately adjustingthe positioner.

The apparatus of my invention can be used in the telemetering oi variousconditions, or the positioning oi any kind oi a movable member, but iorpurposes oi illustration it will be described in connection with themeasuring oi a rate oi 10 the time intervals are not constant but aredependent upon the then iiow rate.

In my invention I may utilize a telemetric transmitter oi any oi theknown designs which give a flow oi current for a period proportional tothe iiow being measured. For example, in the use oi my invention with anapparatus ior measuring a rate oi iiow, it is customary to measure theflow by creating a pressure diiierential therein, such as by a Venturitube. It is well known that the pressure varies as the square oi theflow. However, it is still possible to secure a current of a timeinterval directly proportional to flow by several mechanisms. Forpurposes oi illustration I show in Figure 1 a transmitter ill whichincludes a contact arm ii whose angular podtion irom its zero orleit-hand position varies as the square oi the flow rate. A cam I2 ismounted on a shait II which is driven at constant speed by any suitablemeans, such as a synchronous motor, not shown. The contour of the cam itis what is sometimes called a "square root cam, that is, one in whichthe length oi time of contact between the contact arm ii and the cam i2is the square root oi the position of the contact arm ii (measured iromthe zero or no flow position) so that the length oi time of contactbetween the arm ii and the cam i2 is directly proportional to the rateoi flow through the conduit. The contact arm ii is connected to a sourceof power Ll. by a conductor H which includes coil 2i oi a four polerelay II. The cam I2 is connected to a source of power In by anysuitable means such as brush Ii and conductor I, the brush l5 contactingeither the shait i3 or the cam itself. This circuit, which might bedesignated as the primary circuit, obviously is closed for the periodduring which the contact arm ll contacts the cam I2. Thus the coil 2| oithe relay is energized for a length oi time proportional to the flow oifluid through the conduit.

The four pole relay II is of the non-interlocking yp the core carryingiour poles 2t, 24, 25 and II as shown. Associated with pole 23 arecontacts 21 and II while the contacts 2| and II are associated with pole24. The relay is so constructed and arranged that when the coil 2| isdccncrglzed the poles 23 and 24 are separated from their respectivecontacts, and the circuits including such contacts are open. Contacts 3|and 32 are associated with the pole 25 and conlacts 33 and 34 areassociated with pole 26. These two switches are normally closed when thecoil 2| is dccncrglzed, and the circuits including these switches arebroken when the coil 2| is energizcd. Thus, energizing the coil 2|closes the circuits which include the poles 23 and 24 and opens thecircuits including the poles 25 and 26 and conversely, deenergizing thecoil 2| closes the circuits which include poles 25 and 26 and opens thecircuits which include poles 23 and 24.

Thepositioner or telemetric receiver 40 includes a calibrated scale 4|with which is associated a pointer 42 carried on arm 43. The arm 43 ismounted on a shaft 44 suitably placed in the positioner, such as on abracket 45. While the arm 43 is pivotally mounted with respect to thebracket 45 it is held against free rotation by some suitable means, suchas spring 45, so that friction holds the arm in any position to which itis moved.

A synchronous or constant speed motor 50 is also mounted in thepositioner 40. The motor 50 is connected to the source of power L1 byconductor and to contact 28by conductor 52. Contact 21 is connected tosource of power La by conductor 53. For convenience, the circuit will becalled circuit A. Thus, whenever the coil 2| of the relay 20 isenergized (by contact of contact arm II with cam I2), circuit A isclosed by the pole 23 and the motor 50 will rotate at a constant speedfor the length of time that the contact arm II is in contact with thecam I2. As shown by the arrow, it rotates in a counterclockwisedirection facing the drive shaft 54 of the motor.

One half 56 of a magnetic clutch 55 is rigidly mounted to the shaft 54while the other half 51 is free to rotate with respect to theother half56. The free half 51 of the clutch 55 is provided with an arm 58 havinga contact 59. A tension spring 60 is connected to the free half 51 ofthe clutch 55 to return it to a zero position when it is deenergized.

The magnetic clutch 55 is connected to source of power L1 by conductor6| and to source of power L2 through conductor 62, contact 99 of therelay 90, pole 94, contact 98 and conductor I03 (constituting circuitB). By means to be described below, circuit B is energizedsimultaneously with energizing of circuit A, but is deenergizedindependently of circuit A.

The relay 90 is of the three pole electrically interlocking typeprovided with a coil 9|. This relay has three poles93, 94 and 95.Associated with pole 93 are contacts 96 and 91; associated with pole 94are contacts 96 and 99; and associated with pole 95 are contacts I00 andIOI. As shown in the drawing all three poles-are separated from theirassociated contacts when the coil 9| is deenergized.

The arm 43 also carries a contact 41 so positioned that the contact 59carried by arm 58 binding post I04 01' relay 90. and thence to source ofpower L: as described hereafter. These form circuit C, which is closedwhen coil 2| is deenerglzed and contacts 41 and 59 are together.

It is obvious that while both the motor 50 and the magnetic clutch 55are energized, the arm 55 is carried forward against the action of thespring 50. If the motor 50 should stop before the contact 59 on themotor driven arm 55 reaches contact 41 carried on positioned arm 43, theclutch 55 remains energized and the arm 50 will have been moved anangular position corresponding to the how rate and remain there.

In opposed relationship to synchronous motor 50 is a second motor'l0which may be synchronous or non-synchronous as desired, but which willrotate at greater speed than the motor 50. The shaft II of the motor I0likewise carries a magnetic clutch 12 one half I3 being rigidly securedto the shaft Ii while the other half 14 is free to rotate about theshaft. An arm I5 is mounted on the freely rotating half 14 of the clutchI2. A tension spring 15 is secured to the arm 15 or to the freelyrotating'hali' I4 of the clutch (as shown) to return the arm 15 to azero position when the clutch is deenergized. The

motor 10 and the clutch 12 are simultaneously energized and deenergizedthrough circuit D. This circuit comprises, beginning at source of powerL1, conductor 11, branch conductor I6 to the motor 10 and branchconductor I9 to the clutch l2; branch conductors (from the motor) and 9|(from the clutch) join conductor 82, which leads to contact IOI of therelay thence across pole 95, contact I00, conductor II2, contact 3| (ofrelay 20), pole 25, contact 32, and conductor II3 to source of power L2.

Contacts 29 and 30 of relay 20 are connected to contacts 96 and 91,respectively, of relay 90 by means of conductors IIO and III,respectively. Contact 96 is also connected to source of power L1 throughconductor I06 and contact 91 is connected to source of power L2 throughconductor I02, binding post I05, coil 9|, binding post I04, resistorI01, and conductor I03. This circuit, referred to as circuit E,constitutes an electrical interlock which is first closed when coil 2|is energized and then holds the circuit closed as pole 93 (of relay 90)short circuits contacts 29 and 30 (of relay 20).

At the zero position, just before the beginning of a cycle, the twomotor driven arms 58 and 15 are at their zero position, and both motors50 and 10 are stopped, the circuits serving both motors beingdeenergized. Likewise the two magnetic clutches 55 and I2 aredeenergized. While the poles 25 and 26 (relay 20) are in contact withtheir respective contacts, the circuits D and C respectively, whichinclude those .poles are broken: the pole 95 of circuit Dis separatedfrom its contact points; and circuit C is broken between contact 59 andcontact 41 of pointer arm 43 and also binding post I05 is disconnectedfrom source of power L1. Thus at the beginning of a cycle all of thecircuits are broken and the motors 50 and I0 and the magnetic clutches55 and I2 are deenergized.

When the arm II comes in contact with the cam I2 the primary circuit(which includes the coil 2|) is closed and relay 20 is energized. Thisraises the core, or plunger, 22 of the relay 20, so that pole 23 closescircuit A and pole 24 closes circuit E. Simultaneously circuits D and Care broken at the relay 20. Thus the energizing of the coil 2| in theprimary circuit closes circuit magnetic clutch run. As clutch 12 is Aleading to motor 55, causing it to rotate. Simultaneously, the closingof circuit E energizes coil of relay 95, so that all the contacts ofthis relay are bridged by their respective poles. Raising of pole 95closes circuit B, which energizes 55. Thus the motor 55 and itsassociated magnetic clutch are energized simul- "taneously.

In connection with the closing of circuit E, it will be noted that thebridging of the gap between contacts 95 and 51 by the pole 95 shortcircuits the portion of circuit E in relay 25, thus establishing aholding circuit for relay 95 leading from source of power L1 throughconductor I55, contact 95, pole 93, contact 91, conductor I52, coll 9|,resistor I51, conductor I55 back to L2. This constitutes'an electricalinterlock which maintains coil 9| of relay 95 energized when coil 2| ofrelay 25 becomes deenergized by the movement of the cam I2 away from thecontact arm-l I. Thus the motor 55 and the magnetic clutch 55 aresimultaneously energized so that the arm, 55, is moved forward for thelength of time that the contact II is in contact with the cam I2. Thatis, the arm 55 is moved forward at a constant rate for a period of timedirectly proportional to the rate of flow through a conduit which isbeing measured, since the length of time that the contact arm II is incontact with the cam, I2, is proportional to the rate of flow throughthe conduit. However, the contact will be broken and the coil 2-Ideenergized at the end or such period. When this happens circuit A isbroken and the motor 55 stops.

If the motor 55 should stop before contact 59 on arm 55 reaches contact51 on arm 55 the clutch 55 remains energized by virtue of the holdingcircuit E above mentioned (which among other things holds circuit Bclosed). Thus the arm .55 will remain in its then position and will havemoved forward to an angular position corresponding to the flow rate andremain inthat position as long as the clutch is energized.

It is obvious that simultaneously with the deenergizing of coil 2| ofrelay 25 and the stopping of motor 55, poles 25 and 25 contact theirrespective contacts, thereby closing the circuit D and also closingcircuit C insofar as relay 25 is concerned (circuit C still being brokenbetween contacts 51 and 59). The closing of circuit D simultaneouslyenergizes the second motor 15 and its clutch. Thus simultaneously withthe stopping of synchronous motor 55, the second motor 15 (which asindicated above rotates at a greater speed than the motor 55) begins toalso energized, the arm 15 moves forward. Presently the arm 15 willreach the pointer arm 59 and push it towards arm 55. When the contacts59 and 51 come together they close circuit C, which short circuits ofrelay 95, thereby deenergizing it. With the deenergizati n of coil 9|,plunger 52 of relay 55 drops and of the circuits controlled by it(circuits E, B and D) are broken, whereupon the motor 15 is stopped andsimultaneously the two magnetic clutches 12 and 55 are deenergized. Thefree halves 14 and 51 respectively of the two clutches are returned totheir '0 position by the action of the tension springs 15 and 55respectively. This leaves the pointer arm 55 in the angular positionwhich corresponds to the rate of how being measured. As the pointer arm55 is held in its position by any suitable friction device such asspring 55 when it is not being forcibly moved, it will remain in thisposition the coil 5| Y untilachangeintherateofflowcausesittobe movedeither to the right or to the left.

In the event that the quantity to be measured in any cycle is greaterthan that of the precedin cycle, then it is obvious that the motor andthe clutch 55 will continue energized so long as the primary circuit isclosed, thus causing the arm 55 to rotate through a greater angle andpush the arm 55 to a new position. It is obvious that circuits A and Ewill be closed as they are directly closed by the energization of coil2| of relay 25. Relay 95 will be energized also as circuit C is brokenat relay 25, so that coil 5| is not shunted. Thus the coil 5| remainsenergized so long as the coil 2| is energized, and consequently magneticclutch 55 remains energized as long as the motor 55 is operated.However, immediately upon the breaking of the primary circuit, and theconsequent deenergizing of coil 2|, circult C is simultaneouslyreestablished in relay 25 (and was already closed at contacts 51 and 59when arm 55 contacted pointer 55) thereby short circuiting coil 5| anddeenergizing relay 55. This prevents any operation of the motor 15 orits associated clutch 12. Thus when the motor 55 moves the arm 55through a greater angle than was represented by the previous position ofthe arm 55, the motor 55 and the magnetic clutch 55 remain energized fora length of time corresponding to the rate of flow to be measured.However, immediately upon the breaking or the primary circuit, the motor55 is stopped, the clutch 55 is deenergized and the circuits controllingthe operation of motor 15 are broken so that the arm 55 returns to itszero position and the arm 15 is not moved from its zero position.

If there is no change in flow rate from one cycle to the succeeding one,then the length of time which the motor 55 moves is exactly equal tothat represented by the position of the pointer arm 55, then thecontacts 59 and 51 close simultaneously with the deenergizing of coil 2|thus momentarily establishing circuit C to prevent operation of themotor 15.

' In some instances it is desirable not to be limited to uniform timeintervals between successive operations or motor 55. In prior artdevices the cycle was always uniform and when rate. or flow was low theperiod of rest would be much greater than the period of operation of thepositloner 55. One form of my invention involves the useof non-uniformtime intervals so that upon the return of the arms 15 and 55 to theirpodtions of rest a new cycle is immediately initiated. This permitsfrequent testing when rates of flow are low. The apparatus of thisembodiment is identical with that described in Figure 1 with thefollowing exceptions:

In this, embodiment the transmitting element a synchronous motor I55.However, in this embodiment instead of the cam I20 being placed on theshaft I5I of the motor I55 to rotate constantly with the motor, amagnetic clutch I52 is interposed between the cam I2a and the motor I55.The magnetic clutch I52 has one side, I55, rigidly secured to the shaftl5| of the motor. The other half I55 of the clutch is attached to adriven shaft I55 on which the cam I20 is located. The cam He is similarin shapetothatofcam I2ofrlgure1,butinaddition a tension spring I55 isfastened to the cam tosnapitbacktoitsstartingpositionupon deenergizingthe magnetic clutch I52. In order to start rotation from a set or zeropoint, the shaft I55 is preferably provided with a finger I51 7 whichcomes in contact with the stop I38 at the zero position.

Preferably the cam I2a will be insulated at the very tip, as shown atI39, so that on very small flows, say up to 4% oi' the usual flow, therewill be no electrical contact between the arm Na and the cam I2a. I alsoprovide an extension member I40 on the cam, which is adapted to bridgethe gap between contacts I and I42 when the cam I2a returns to its zeroP i n h establishing a circuit through conductors I43 and I44, thelatter being connected to source of power I Ll through conductor I45.

The contact arm Ila diflers from that shown in Figure 1 in that itpreferably has an extension I20 separated from the arm IIa by aninsulator I2I. The extension I20 engages a contact strip I22 which is soarranged that at very low flows, say less than 4%, the extension I20will have overrun the contact strip I22. This construction of the arm Ila is preferred in order to provide means for preventing rotation of camI2a at extremely low flows, as hereinafter described.

It is also necessary to change the relay 90 from a three pole switch toa four pole switch 90a, with one pole in the closed position when therelay is deenergized. Thus the plunger 92a will carry an additionalpole, I50, which, when the coil 9Ia is deenergized, will be resting uponcontacts I5I and I52. I

It is also necessary to add to the apparatus two additional-relays: I10,which contains a three pole electrical interlocking switch; and I90,which contains a two pole non-interlocking switchboth of which will bedescribed in detail here-' after.

The arm 58 of posltioner 40, in this embodiment is also provided with asecond contact I 60 joined to conductor I43. Associated with contact I60is a fixed contact I6I which is located at the zero position. Thus, atthe start of a measuring cycle the two are in contact with each other.Contact I6I is connected by conductors I62 and I63 to contact I5I of therelays 90a. Contact I6I is also connected by means of conductors I62 andI64 to binding post I18 of the relay I10. Also associated with thecontact I60 is a third contact I65 which is so positioned that contactI60 comes in contact therewith when it has traveled a, short distance,such as 3 or 4 per cent of the angular travel of arm 58. Contact I65 isconnected to binding post I 96 of a two pole interlocking relay I90 byconductor I66.

The extension member I40 of the cam I2a is so arranged that it maintainsa contact between its associated contact points I and I42 for a lengthof time corresponding to some predetermined portion of the travel of thearm 58 such as 3%. It will be seen that the circuit through contact I60and the contacts I and I42'and the arm I40 will be made through thecontact I6I and conductors I62 and I64, as hereinafter described, at theinitiation of a cycle and for a short period thereafter. That circuit isbroken and shortly thereafter, say after 3% of the travel of the arm 58,a new circuit will be initiated through contact I65 and line I66 ashereinafter described.

The three pole switch I10 (provided with poles I 12, I13 and I 14) isoperated by energizing coil I1I while the two pole switch I90 (providedwith poles I92 and I93) is operated by energizing coil I9I.

Contact I15 of relay I10 is joined, as shown, to source of power L1through conductor I45. Conductor I64 leading from the contact I6Iterminates at binding post I18 of the relay I10. A conductor I8I leadsfrom the binding post I18 of relay I10 to contact I94 of'relay I90. Oneend of the coil,I1I is also connected to binding post I18 and the otherto binding post I82, thence through resistor I83 and binding post I84 tosource of power L2.

A conductor I85 also leads from binding post I84 to binding post I19 ofrelay I10. Opposite binding post I19 is contact I16, from which leadsconductor I86 to coil I9I of relay I90 and thence to binding post I96 ofthe same relay.

Binding post I80 is connected to source of power Ll by conductor I81.Contact I11 is connected to the contact strip I22 by conductor I88. Theextension I20 is connected to the magnetic clutch I32 by line I23.Conductor I89 leads from the magnetic clutch I32 to source of power In.

Thus the energizing of the relay I10 closes a circuit through themagnetic clutch, thereby energizing it, if the flow'is more than thepredetermined minimum flow (such as 4%). Of course if the arm IIa ispositioned at less than the predetermined minimum the extension I 20 hasoverrun the contact strip I22 and the circuit is maintained open and theclutch is not energized. This construction prevents operation of the camI2a when flows are at a minimum. Such operation might otherwise bepossible, and as the circuits would not be deenergized the cam wouldotherwise be driven in a complete circle with danger to the motor andclutch mechanism.

Contact I95 of the two pole relay I90 is connected to contact I52 of therelay 90a by conductor I98 and binding post I91 of the two pole switchis connected to binding post I82 by conductor I99.

As the cam in is returned to its zero position by the spring I36 and arm58 is returned to its zero position by spring 60, a circuit F isestablished leading from source of power Ll through conductors I45 andI44, contact I42, extension member I 40, contact I, conductor I43,contacts I60 and I6I, conductors I62 and I64, binding post I18, coilI1I, binding post I82, resistor I83 and binding post I84 to source ofpower L2. This circuit energizes the relay I10 and poles I12, I13 andI14 are moved to contact the contacts I16, I16 and I11 respectively. Itwill be noted that pole I12 shunts the circuit F just described so thatcurrent flows from source of power Li, conductor I45, contact I15, poleI12, coil I1I, resistor I83 back to source of power L2. This constitutesa holding circiut and holds the relay I 10 energized until the circuitis broken as hereinafter described.

Simultaneously with the closing of this holding circuit, pole I13 alsocomes in contact with contact I16, but no circuit is established untilthe arm F is established from there through conductor I66, binding postI96 of relay I90, coil I8I, conductor I86, contact I16, pole I13,binding post I19, conductor I85, to binding post I84 and thence to 7source of power L2. This circuit, energizes coil I 9| to operate therelay I to move poles I92 and I93 to the closed position.

Simultaneously with the energizing oi coil III (which is alsosimultaneous with the energizing arm 58) pole I14 is moved to establishcontact .between binding post I88 and contact I11, thereby (assumingextension I28 engages contact strip I22) closing the circuit G connectedto the magnetic clutch I32, energizing it to drive the cam I20 until thecircuit is deenergized as hereinafter described.

It is obvious that as the cam I2a rotates the arm I48 moves out ofcontact with contact points I and I42 so that the circuits F and F arebroken at these points.

When the coil I9I of relay I98 is energized, pole I92 is moved toestablish contact between contact. I94 and binding post I98 to provide aholding circuit for coil I9I leading from source of power L1 throughconductor I45, contact I15, pole I12, binding post I18, conductor I8I,contact I94, pole I92, binding post I98, coil I9I, conductor I88,contact I15, pole I18, binding post I19, conductor I85 and binding postI84 to source of power L2.

The movement of pole I93 to establish contact between contact I95 andbinding post I91 connects conductor I98 back to source of power Lathrough conductor I99, binding post I82, resistor I83 and thus to 1.0.However no circuit is established as relay 98a is energized and pole I58is removed from its associated contacts. This circuit therefore does notbecome effective for the time being and it is not closed until theoperation of the positioner 48 and relays 28 and 98a are complete, asdescribed in connection with Figure. 1. When however the cycle ofoperation of the positioner 48 is complete and the arm 58 returns to itszero position and the coil 9Ia is deenergized, then a circuit isestablished from Ll, through contact I15, pole I12 and binding post I18of relay I18, conductors I84 and I89, contact II, pole I58 and contactI52 of relay 98a, conductor I98, contact I95, pole I93 and binding postI91 of relay I98, conductor I99, resistor I88, binding post I84 to La.This short circuits coil Ill and deenergizes both relays I18 and I98.The deenergizing of coil I1I also results in breaking the circuit to themagnetic clutch I82, whereby the spring I 88 returns the cam I2a to itszero position which immediately closes circuit F to initiate a new cycleof operation.

Manifestly various modifications and variations of the invention hereindescribed will be apparent to those skilled in the art. Accordingly, theappended claims are to be given an interpretation commensurate withthenovelty herein described and as broad as may be permitted by prior art.

I claim:

1. A telemetering system including a transmitter so constructed andarranged as to give an impulse of a time duration proportional to thefunction being measured, a receiving instrument and a transmission linefrom said transmitter to said receiving instrument, said receivinginstrument comprising a positionable element, a constant speed motor, amagnetic clutch connected to said motor, and a pusher arm connected tosaid clutch and adapted to push said positionable element in onedirection; a second motor, a second magnetic clutch connected to saidsecond motor, a second pusher arm connected to said second clutch andadapted to push said positionable element in the opposing direction, andrelay means including a coil in said transmission line adapted to closea circuit controlling operation of said synchronous motor upon theenergizing of said coil, to energize said first mentioned magneticclutch simultaneously with the operation of the synchronous motor andmaintain it energized until the last, occurring of either the contact ofsaid first pusher arm and said positionable element or the deenergizingof said coil, to close a circuit simultaneously energizing said secondmotor and said second magnetic clutch upon termination of operation ofthe first motor and to open said last mentioned circuit when said firstpusher arm contacts said positionable member.

2. The apparatus of claim 1 comprising also means for immediatelyinitiating a new cycle of transmission by said transmitting element upontermination of a cycle of operation of the receiving instrument.

3. The apparatus of claim 1 wherein said transmitter comprises aconstant speed motor, a magnetic clutch connected to the shaft of saidmotor, a cam driven by said magnetic clutch, means for returning saidcam to a, zero position upon deenergizing of said clutch, means forenergizing said clutch upon return of said cam to said zero position,and means for deenergizing said clutch upon termination of operation ofsaid receiving instrument.

4. A telemetric receiver comprising a movable member, a first pusheradapted to push said movable member in a forward direction and a secondpusher adapted to push said movable member in a reverse direction, aconstant speed motor adapted to drive said first pusher, a magneticclutch connecting said first motor to said first pusher, a second motoradapted tci move said second pusher, a magnetic clutch connecting saidsecond motor to said'second pusher, a relay adapted to be energized fora period of time corresponding to the quantity to be measured, a circuitfrom said relay to said constant speed motor, means for closing saidcircuit for a period corresponding to the energizing of said relay, asecond circuit connected to said first magnetic clutch, means forclosing said second circuit simultaneously with the closing of saidfirst circuit and including a holding relay adapted to maintain saidcircuit closed so long as said first relay is energized, and until saidfirst pusher contacts said movable member, a third circuit to saidsecond motor and said second clutch, means for closing said thirdcircuit upon the deenergizing of said first relay and breaking saidthird circuit when said first pusher comes in contactwith said movablemember, and means for returning said pushers to their zero position.

5. A telemetering system including a transmitter so constructed andarranged as to give an impulse of a time duration proportional to afunction being measured; a receiving instrument, said receivinginstrument comprising a positionable element, a constant speed motor, amagnetic clutch connected to said motor, and a pusher connected to saidclutch and adapted to push said positionable element in one direction, asecond motor, a second magnetic clutch connected to said second motor, asecond pusher connected to said second clutch and adapted to push saidpositionable element in the opposing direction; a transmission line fromsaid transmitter to said receiving instrument; and a relay meansincluding a coil in said transmission line adapted to close a circuit tosaid constant speed motor so long as said coil is energized, to close asecond circuit to said first mentioned magnetic clutch so long as saidcoil is energized and thereafter to hold said circuit closed so long asthe positionable member ofsaid receiving instrument and said firstpusher are not contacting one another, and to close a third circuit tosaid second motor and said second magnetic clutch upon the deenergizingof said coil and to hold said third circuit closed so long as thepositionable member of said receiving instrument and said first pusherare not in contact.

6. A telemetei'ing system including a transmitter so constructed andarranged as to give an impulse of a time duration proportional to afunction being measured; a receiving instrument, said receivinginstrument comprising a positionable element, a constant speed motor, amagnetic clutch connected to said motor, and a pusher connected to saidclutch and adapted to push said positionable elementin one direction, asecond motor, a second magnetic clutch connected to said second motor, asecond pusher connected to said second clutch andadapted to push saidpositionable element in the opposing direction;

a transmission. line from said transmitter to said receiving instrument;a first relay' including a coil in said transmission line; a holdingrelay;

an energizing circuit from said first relay to said holding relay soarranged as to energize said holdingvrelay upon the energizing of said0011; a shunting circuit from said holding relay to the positionableelement and said first pusher of the receiving instrument and through anormally closed contact of said first relay, whereby theholding relay isdeenergized upon the contacting of said element and said arm and thedeenergizing of said first relay; a first motor circuit from a normallyopen contact of said first relay to said constant speed motor; a firstclutch circuit from a normally open contact of said holding relay tosaid first mentioned magnetic clutch; and a second motor circuit to saidsecond motor and said second magnetic clutch from a normally opencontact of said holding relay and a normally closed contact of saidfirst relay.

7. A telemetering system which comprises a receiving instrument, saidreceiving instrument comprising a positionable element, a constant speedmotor, a magnetic clutch connected to said motor, and a pusher connectedto said clutch and adapted to push said positionable element in onedirection, a second motor, a second magnetic clutch connected to saidsecond motor, a second pusher connected to said second clutch andadapted to push said positionable element in the opposing direction, afirst relay, a holding said first relay to said constant speed motor, a

first clutch circuit from a normally open contact of said holding relayto said first mentioned magnetic clutch, a second motor circuit to saidsecond motor and said second magnetic clutch from a normally openvcontact of said holding relay and a normally closed contact of saidfirst relay; and a transmitting instrument, said transmitting instrumentcomprising a member positioned by the quantity to be measured, a camintermittently contacting said member, said cam being so constructed andarranged as to contact said member for a period of time proportional tothe quantity being measured, a constant speed motor, a magnetic clutchconnecting said cam to said motor,

means for returning said cam to a zero'position upon deenergizing ofsaid clutch, means including a relay energized by a circuit closed uponreturn of the cam and the first pusher of the receiving instrument totheir zero positions for immediately reenergizing said clutch, and ashunting circuit to said last mentioned relay from a normally closedcontact of said holding relay of the receiving instrument, whereby saidclutch is deenerglzed upon termination of operation of said positionableelement of the receiving instrument; and a primary circuit to said firstrelay of the receivinginstrument through said cam and said memberpositioned by the quantity being measured.

- WALTER H. GREEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

